Is a 1 phase 3hp motor as powerful as a 3 phase 3hp motor?
Thanks

Brett

Thomo said:

Is a 1 phase 3hp motor as powerful as a 3 phase 3hp motor?
Thanks

Brett

They are equally powerful, but one draws less current per input wire( but has more input wires).

And one should have no current on the neutral wire( most don’t even need the neutral wire)

Guessing a HP is a HP is a HP.

transition said:

Guessing a HP is a HP is a HP.

Yes. A three phase motor is often smaller, more efficient, and runs smoother than a single phase equivalent. A three phase motor also has the benefits of being wired up in “Star” or “Delta” configuration (each has their own advantages) and the direction can be reversed easily.

However, a single phase motor has the advantage of being able to run off domestic supplies. :)

And some big 3ph motors can be run in both star and delta modes for start up and then normal running.

One major disadvantage of single phase motors is that they require a starting capacitor. Normally the first thing to fail, that or the switch that takes it out of circuit.

BTW, what is a horse power? Le Système international d’unités is the only thing that I’ll accept, Pilgrim!

Thanks all

I have a old 4kw single phase on a drill that I was hoping to use on my Compressor whilst the 5hp 3 phase motor gets rewound
Asuming I can get the pully wheel on the shaft.

Compressors take quite a bit of starting, especially if pressure on outlet, which there often is, so the right drive ratio and suitable start power is required for worst case situation.

sibeen said:

One major disadvantage of single phase motors is that they require a starting capacitor. Normally the first thing to fail, that or the switch that takes it out of circuit.

BTW, what is a horse power? Le Système international d’unités is the only thing that I’ll accept, Pilgrim!

746W

Dad built a compressor while back from twin-cylinder large refridgeration compressor, large LP gas bottle, and mentioned to me it was throwing the circuit breaker after considerable period, I mentioned it probably was not coming out of start and had a look and sure enough wasn’t, so he added pulley reduction and all went well, turned out to be one of the quietest compressors i’ve ever heard, and brings that big bottle up to pressure quick too, so all good.

transition said:

Dad built a compressor while back from twin-cylinder large refridgeration compressor, large LP gas bottle, and mentioned to me it was throwing the circuit breaker after considerable period, I mentioned it probably was not coming out of start and had a look and sure enough wasn’t, so he added pulley reduction and all went well, turned out to be one of the quietest compressors i’ve ever heard, and brings that big bottle up to pressure quick too, so all good.

On mcClouds man made home he made gas good enough to run a generator from heated up sheep poo. Of course he used a gas cylinder to heat the poo so the energy equation probably doesn’t work but it was impressive for something so simple.

>On mcClouds man made home he made gas good enough to run a generator from heated up sheep poo. Of course he used a gas cylinder to heat the poo so the energy equation probably doesn’t work but it was impressive for something so simple.

Just was watching that, but guy tends to make me feel unwell after a while.

Yeah ‘producer gas’ think it were refered to in old days, have a box with coals in it (wood or whatever), but with no flame, intake from petrol type engine draws gas in. Perhaps not exactly same gas as the grass, not sure, still same idea.

http://en.wikipedia.org/wiki/Producer_gas

BTW, what is a horse power?
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How much work it takes a pony to turn a mill wheel.

And here is the science bit…

Then times it by two because it was a small horse.